CN107949979B

CN107949979B - AC generator for vehicle

Info

Publication number: CN107949979B
Application number: CN201580082862.6A
Authority: CN
Inventors: 秋吉雅夫; 南真一郎; 本庄健太郎
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2015-09-15
Filing date: 2015-09-15
Publication date: 2020-05-19
Anticipated expiration: 2035-09-15
Also published as: EP3352344A4; WO2017046859A1; JP6366851B2; US20180183297A1; MX2018003203A; EP3352344A1; CN107949979A; JPWO2017046859A1

Abstract

A vehicle AC generator is provided with narrow-pitch portions (63) and wide-pitch portions (62) having a blade pitch in the circumferential direction of a fan (11b) fixed annularly to a pole core (10), and two or more wing portions (54) are arranged in the narrow-pitch portions (63) so as to be in contact with the end surfaces of two or more adjacent claw poles (60). According to the structure, the deformation of the wing part (54) caused by the rotation can be restrained, and the increase of the noise generated by the fan (11b) can be restrained.

Description

AC generator for vehicle

Technical Field

The present invention relates to an alternator that outputs an ac voltage from a stator coil in accordance with rotation of a rotor, and more particularly to an automotive alternator that charges an in-vehicle battery and supplies electric power to an in-vehicle electric device.

Background

In recent years, in automotive alternators, engine noise has been reduced in view of social needs aimed at reducing noise outside the vehicle and improvement in commercial quality due to improvement in silent property inside the vehicle. As the engine noise decreases, the fan noise of the automotive alternator that rotates at a relatively high speed becomes very loud. The noise of the fan refers to noise of cooling air generated in the radial direction by the fan, noise of interference sound of the coil edge, the magnetic pole, and the like of the stator cooled by the air, noise of air generated by rotation of the fan itself, and the like. For example, as shown in fig. 19 of patent document 1, the following is disclosed: among the 8-pole claw poles of the rotor, a pair of claw poles located symmetrically with respect to the rotation axis are arranged so that two claw poles are in contact with each other to form a blade of the fan, and the other claw poles are arranged so that one blade is in contact with each other.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 3279258

Patent document 2: japanese patent laid-open No. Hei 3-218241

Disclosure of Invention

Technical problem to be solved by the invention

Therefore, the interval between the two wings disposed so that the two claw poles contact each other is narrow, and the interval between the wings disposed so that one claw pole contacts one is wider than the above-described interval. In the case of the above-described arrangement of the blades, the frequency of the noise generated by the blades having a narrow blade interval is greatly different from the frequency of the noise generated by the blades having a wide blade interval, and if the frequency of the noise generated by the blades having a wide blade interval coincides with the frequency of the noise generated from the claw pole, a larger noise is generated.

Further, since the blades having a narrow blade interval are disposed to face the rotation shaft, the period of the blade interval changes at intervals of 180 degrees, and noise generated by the periodicity of the blade interval is amplified and increased.

Technical scheme for solving technical problem

The vehicle AC generator of the present invention comprises: a magnetic pole core accommodated in the frame, having claw magnetic poles, and rotating in synchronization with the rotating shaft; and a fan that is fixed to the pole core in a ring shape, and that sends cooling air introduced from the outside into the frame by rotation of the fan to cool the stator winding and the ac output rectifying element by the cooling air, wherein the cooling fan includes wing portions formed of a main plate and a plurality of wings erected from the main plate, the wings are provided in a first region and a second region in a circumferential direction at different pitches, the number of the wing portions is set to be larger than the number of poles of the pole core, and two or more wing portions are in contact with respective end faces of two or more adjacent claw poles.

Effects of the invention

According to the vehicle ac generator of the present invention, it is possible to suppress deformation of the wing portion due to rotation and to suppress an increase in noise generated by the fan.

Drawings

Fig. 1 is a longitudinal sectional view of a vehicle ac generator according to a first embodiment of the present invention.

Fig. 2 is a perspective view of a rotor of a vehicle alternator according to a first embodiment of the present invention.

Fig. 3 is a plan view of the rear fan according to the first embodiment of the present invention.

Fig. 4 is a diagram showing a relationship between the blade pitch number and the pitch of the rear fan according to the first embodiment of the present invention.

Detailed Description

The first embodiment is described.

Fig. 1 is a longitudinal sectional view showing a vehicle ac generator 1 according to a first embodiment of the present invention.

In fig. 1, an automotive alternator 1 includes: a casing 4, the casing 4 being composed of a front holder 2 and a rear holder 3 made of aluminum and each having a substantially bowl shape; a shaft 6, the shaft 6 being rotatably supported by the housing 4 via a pair of bearings 5; a pulley 7, the pulley 7 being fixed to an end of the shaft 6 extending toward the front side of the housing 4; a rotor 8, the rotor 8 being fixed to the shaft 6 and disposed in the housing 4;

fans

11a and 11b, the

fans

11a and 11b being fixed to both end surfaces of the rotor 8 in the rotation axis direction 18; a stator 12, the stator 12 being fixed to the housing 4 so as to surround the rotor 8; a pair of slip rings 15, the slip rings 15 being fixed to an extension of the shaft 6 extending toward the rear side of the housing 4 and supplying current to the rotor 8; a pair of brushes 16, the brushes 16 sliding on the surface of each slip ring 15; a brush holder 17, the brush holder 17 accommodating the brush 16; a voltage regulator 22, the voltage regulator 22 being disposed on the rear side of the rear bracket 3 and regulating the magnitude of the ac voltage generated in the stator 12; a connector 24, which is disposed on the rear side of the rear bracket 3, and which is used for inputting and outputting signals between the voltage regulator 22 and an external device (not shown); a rectifier 30, which is disposed behind the rear bracket 3, and which rectifies an ac voltage generated in the stator 12 into a dc voltage; and a protective cover 40, wherein the protective cover 40 is attached to the rear bracket 3 so as to cover the brush holder 17, the voltage regulator 22, and the rectifying device 30.

The rotor 8 includes: a field winding 9 through which a field current flows to generate a magnetic flux; and a pole core 10, wherein the pole core 10 is provided so as to cover the field winding 9, and forms a magnetic pole by a magnetic flux of the field winding 9. Further, the stator 12 includes: a cylindrical stator core 13; and a stator winding 14, the stator winding 14 being wound around the stator core 13 and generating an alternating current by a change in magnetic flux from the field winding 9 as the rotor 8 rotates.

The stator 12 is disposed such that the stator core 13 is sandwiched by the open ends of the front bracket 2 and the rear bracket 3 from both sides in the axial direction to surround the rotor 8.

The rear bearing 5 is fixed to a bearing mounting portion 25 via a bender (holder) 26, and the bearing mounting portion 25 is provided on the rear bracket 3.

Fig. 2 is a perspective view of the rotor 8 as viewed from the rear side of the automotive alternator 1. The end face of the pole core 10 is a flat surface from the vicinity of the shaft 59 to the chamfered portion 61 of the side face of the claw pole 60 of the pole core 10, and the rear fan 11b is fixed to the flat portion by welding or the like. The rotor 8 rotates in the rotational direction (the direction of arrow 50). The rear fan 11b is manufactured by a bending method in which a groove substantially along the outer contour of the blade 52 is formed in the main plate 51 (see, for example, fig. 7 of patent document 2), and a hole 53 slightly larger than the outer contour of the blade 52 is formed in the rotation direction of the blade. The fin groove end 54 is an inner circumferential end of the groove, and remains on the main plate 51 even after fin forming. When the rotor 8 rotates, the wing portion 56 formed by joining the main plate 51 and the wing 52 radially outward (in the direction of arrow 55) of the adjacent wing groove end portion 54 receives a centrifugal force, and is largely deformed.

The blade 52 is connected to the main plate 51 at the root of the blade, and is erected at a right angle. As shown in the plan view of the rear fan 11b in fig. 3, the blade 52 is formed in an S-shaped cross section that smoothly connects the arc shape 52a on the rear edge side with the center located rearward in the rotational direction and the arc shape 52b on the front edge side with the center located forward in the rotational direction and that is gradually displaced from the rear edge, which is the outer peripheral end, toward the front edge, which is the inner peripheral end, toward the front edge, which is the outer peripheral end. As shown in fig. 2, the height h of the wing 52 gradually increases from the leading edge 58 toward the wing tip 57 of the wing 52.

Next, the operation of the vehicle ac generator 1 configured as described above will be described. In the automotive alternator 1, the six-phase alternator having 16 poles and 96 slots operates, but the number of poles and the number of slots are not limited to this.

In the vehicle ac generator 1, a current is supplied from a battery (not shown) to the field winding 9 of the rotor 8 via the brushes 16 and the slip rings 15, and magnetic flux is generated. N poles and S poles are alternately formed in the circumferential direction on the outer circumferential surface of the pole core 10 by the magnetic flux. On the other hand, the torque of the engine is transmitted from the output shaft of the generator to the shaft 6 via a belt (not shown) and a pulley 7, and the rotor 8 is rotated. Thereby, the rotating magnetic field acts on the stator winding 14 of the stator 12, and an electromotive force is generated in the stator winding 14. The alternating current generated by the electromotive force is rectified by the rectifying device 30 to charge the battery or is supplied to an electrical load mounted on the vehicle.

The

fans

11a and 11b are rotated in conjunction with the rotor 8. On the front side, the cooling air is sucked into the front frame 2 from the front suction holes 2a and flows to the vicinity of the rotor 8 in the rotation axis direction 18, where it is bent in the centrifugal direction by the front fan 11a and discharged from the front discharge holes 2 b. On the rear side, the cooling air is sucked into the protective cover 40 from the suction port provided in the protective cover 40, passes through between the heat radiation fins provided in the positive-side heat sink 31 and the negative-side heat sink 32, flows toward the rear suction port 3a of the rear bracket 3, and flows in the direction opposite to the rotation axis direction 18 to the vicinity of the rotor 8, where the cooling air is bent in the centrifugal direction by the rear fan 11b and discharged from the rear discharge port 3 b.

A part of heat generated from the stator 12 is bent radially outward by the

fans

11a, 11b from the coil end 12a and radiated to the cooling air discharged from the front side exhaust holes 2b and the rear side exhaust holes 3b, and further, a part of heat generated from the stator 12 is transferred to the front chassis 2 and the rear chassis 3 and radiated toward the cooling air from the plurality of front side ribs 19 and the rear side ribs 20 of the front side exhaust holes 2b, whereby the stator 12 is cooled. The positive-side rectifying element and the negative-side rectifying element of the rectifying device 30 are cooled by cooling air that flows between the heat dissipating fins provided on the positive-side heat sink 31 and the negative-side heat sink 32.

Here, the rear fan 11b and the pole core 10 of the present invention will be explained.

The rotor 8 of the vehicle alternator 1 rotates at a speed two to three times the rotational speed of the engine, and therefore, frequently rotates at a high speed of 10000rpm or more. When the rotor rotates at a high speed, a large centrifugal force is applied to the wing portion 56 including the wing 52, and when the allowable stress of the material of the wing is exceeded, the wing portion 56 is deformed so as to move radially outward and to the opposite side to the rotational axis direction 18.

When the wing portions 56 are deformed as described above, the height h of the wing 52 is lowered, and thus the amount of cooling air generated by the rear fan 11b is lowered, and the temperature of each component is raised. Further, since the blade tip 57 moves radially outward, it may collide with the coil side end 12a of the stator 12 and the stator core 13 and be damaged.

In order to prevent the deterioration of the cooling performance and the breakage, it is necessary to suppress the deformation of the wing portion 56 including the wing 52.

The frequency of the noise generated from the pole core 10 is related to the number of poles, and in the present configuration, since the frequency is eight times the number of revolutions, when the number of blades is eight, the noise frequency of eight times the number of revolutions is amplified, and the noise is increased.

In order to suppress an increase in noise and secure the cooling air volume, it is necessary to increase the number of blades to more than the number of poles, but in the case of a fan formed by bending a metal plate with slits cut therein, since the main plate 51 connected to the root portions of the blades 52 is provided in the direction opposite to the rotational direction and the main plate 51 is not provided in the rotational direction, the circumferential distance between the blade groove end portions 54 of adjacent blades is small, and the blade portions 56 are easily deformed.

Further, as shown in fig. 2, the wide-pitch portions 62 and the narrow-pitch portions 63 of the fins 52 are provided at one location in the circumferential direction. The relationship between the wing pitch number and the pitch is shown in fig. 4. As shown in fig. 3, the wing pitch number is a number assigned to each pitch around the time of reversal with one pitch of the narrow-wing-pitch portion 63 designated as 1 as a starting point (in fig. 3, the wing pitch number is assigned to 13). The adjacent spacing of the narrow-spaced portions 63 varies slightly. On the other hand, the average fin pitch of the wide pitch portion 62 is 1.3 to 1.5 times the average fin pitch of the narrow pitch portion 63, and the pitch in the vicinity of the center of the wide pitch portion 62 (fin pitch numbers 11 and 12 in fig. 4) is changed by the same amount as the pitch of the narrow pitch portion 63. Further, by arranging the vanes 52 in an amount larger than the number of poles of the magnetic pole core 10, it is possible to suppress an increase in noise caused by the periodicity of the vane intervals.

However, with the above configuration, the circumferential distance between the wing groove ends 54 of the wing portions 56 located in the narrow-pitch portions 63 becomes smaller.

Therefore, in order to suppress the deformation of the wing portions 56, the wings 52 of the narrow-pitch portion 63 are arranged such that, for example, two

wing portions

56a and 56b are in contact with the flat surface portion of the end surface of one claw pole 60a, the wing portion 56a is in contact with the flat surface portion of the end surface of the claw pole 60a on the side closer to the wing groove end portion 54a, and the outer peripheral side is arranged between the claw pole 60a and the adjacent claw pole 60 b. The outer peripheral side of the other wing portion 56b is brought into contact with the flat surface portion of the end surface of the claw pole 60a, and the claw pole 60a and the adjacent claw pole 60c are arranged on the side closer to the wing groove end portion 54 b. With the above configuration, the positional relationship between one claw pole 60 and two blades 52 is set as one structure, and the structure is disposed adjacent to the narrow-pitch portion 63 of the blades 52, thereby suppressing the deformation of the blades and suppressing the increase of noise.

As described above, in the first embodiment, by disposing the claw pole 60 and the blade 52, it is possible to suppress deformation of the blade portion due to rotation, suppress a decrease in cooling performance due to a decrease in air volume, and suppress an increase in noise generated by the fan.

In addition, the present invention can be modified and omitted as appropriate within the scope of the present invention. Note that although only the rear side is mentioned in the present embodiment, the same effects such as noise reduction and wing deformation suppression can be achieved even on the front side by providing the fan and the pole core in the same relationship as in the present embodiment.

Description of the symbols

1 an automotive alternator;

2, a front bracket;

2a front side air suction hole;

2b a front side exhaust hole;

3, a rear bracket;

4, a shell;

5, a bearing;

6 shafts;

7 belt wheels;

8, a rotor;

9 exciting the winding;

10 magnetic pole iron core;

11a front fan;

11b rear fan;

12a stator;

13 a stator core;

14 stator windings;

15 collector rings;

16 electric brushes;

17 brush holders;

18 the direction of the axis of rotation;

19 a front rib;

20 rear side ribs;

22 a voltage regulator;

24 connectors;

25 bearing mounting parts,

26 a bender;

30 a rectifying device;

31 a positive side heat sink;

a 32 negative-side heat sink;

40 a protective cover;

51 a main board;

52 wings;

53 holes;

54. 54a, 54b wing slot ends;

56. 56a, 56b wing;

57 wing front end;

60. 60a, 60b, 60c claw poles.

Claims

1. An automotive alternator comprising: a magnetic pole core accommodated in the frame, having claw magnetic poles, and rotating in synchronization with the rotating shaft; and a fan fixed to the pole core in an annular shape, for sending cooling air introduced from the outside into the frame by rotation of the fan, and cooling the stator winding and the ac output rectifying element by the cooling air,

wherein the fan includes wing portions each including a main plate and a wing standing from the main plate, the number of the wing portions is set to be larger than the number of poles of the magnetic pole core, and two or more of the wing portions are in contact with respective end surfaces of two or more of the adjacent claw magnetic poles,

in the case of dividing the circumferential direction into two regions, a first region and a second region, adjacent blades are disposed at different pitches in each region, and the average blade pitch of the first region is formed to be as wide as 1.3 to 1.5 times the average blade pitch of the second region,

the first region has a wider wing pitch than the second region, and has a portion in the vicinity of the center of the first region where the difference in angle between adjacent pitches is the same as the wing pitch of the second region.

2. The vehicular alternator according to claim 1,

the wing has a groove formed in the main plate along the outer contour of the wing, is erected by bending, and is formed in front of the wing in the rotation direction, the hole being larger than the outer contour of the wing.

3. The vehicular alternator according to claim 2,

in the second region, the two wing portions are disposed so as to contact the flat surface portions of the end surfaces of the first magnetic claw poles, the first wing portion is disposed so that the end portion of the first wing portion that is closer to the inner circumferential side end of the groove contacts the flat surface portions of the end surfaces of the first magnetic claw poles, the tip end side of the first wing portion is disposed between the adjacent second magnetic claw poles and the first magnetic claw poles, the tip end side of the second wing portion is disposed so as to contact the flat surface portions of the end surfaces of the first magnetic claw poles, and the second wing portion is disposed so that the end portion of the second wing portion that is closer to the inner circumferential side end of the groove is disposed between the adjacent first magnetic claw poles and the adjacent third magnetic claw poles on the.

4. The vehicular alternator according to any one of claims 1 to 3,

the blade has an S-shaped cross section formed by smoothly connecting an arc shape on the trailing edge side with the center thereof located rearward in the rotational direction of the rotary shaft and an arc shape on the leading edge side with the center thereof located forward in the rotational direction.